Brazile took over the DNC as interim chair following Debbie Wasserman Schultz's sudden resignation during the Democratic National Convention. Once she was at the party's helm, Brazile wrote that she discovered an agreement that "specified that in exchange for raising money and investing in the DNC, Hillary would control the party's finances, strategy, and all the money raised. Her campaign had the right of refusal of who would be the party communications director, and it would make final decisions on all the other staff."

This agreement has been seized on by everyone from President Trump to Massachusetts Sen. Elizabeth Warren as proof that the DNC "rigged" the 2016 primary for Clinton.

The DNC and former Clinton staffers pushed back on Brazile's claim but never outright denied it.

In a letter to DNC members, Chairman Tom Perez noted that the party reached joint fundraising agreements with both Clinton and Vermont Sen. Bernie Sanders. "The joint fundraising agreements were the same for each campaign except for the treasurer, and our understanding was that the DNC offered all of the presidential campaigns the opportunity to set up a [joint fundraising agreement] and work with the DNC to coordinate on how those funds were used to best prepare for the general election."

That may be true — but two Democratic officials tell NPR that Brazile and Perez are referring to two different things. In addition to that joint fundraising agreement the DNC reached with both campaigns, the party and the Clinton campaign struck that separate memorandum of understanding giving the campaign staffing and policy oversight.

That document was signed on Aug. 26, 2015 — before, among other things, Vice President Joe Biden ruled out a run for president.

The DNC has not denied this characterization or timeline.

A Democratic official who has reviewed the document pointed out that in addition to the Clinton signoffs Brazile characterized, it included language stating that "nothing in this agreement shall be construed to violate the DNC's obligation of impartiality and neutrality through the Nominating process" and that "all activities performed under this agreement will be focused exclusively on preparations for the General Election and not the Democratic Primary."

The agreement also noted that the DNC "may enter into similar agreements with other candidates." (Read the full memo below.)

Still, Sanders' 2016 campaign manager, Jeff Weaver, said the agreement was the latest evidence the DNC tried to tip the scales against his candidate. He and other Sanders backers have regularly pointed to the party's scheduling of debates on weekend nights as one example of how DNC officials tried to aid Clinton's campaign.

"I think the DNC should apologize to the millions and millions of people who put their heart and souls into the campaign on both sides, frankly," Weaver told MSNBC Friday. "There are many people who campaigned for Hillary believing it was a fair process. It was not a fair process. And those people are the people who the Democratic Party has to re-establish faith with — the people, the rank and file of this party — allied, independents and other people." (Weaver did not respond to multiple requests for comment from NPR.)

Clinton campaign manager Robby Mook appeared on CNN Friday night and called "laughable" assertions that the agreement rigged the primary against Sanders. Among other things, he pointed to the fact that the memo states that joint efforts were to be focused on the general election.

"The DNC came to our campaign and said, 'We need help. We're not prepared for the general election,'" Mook said. Regarding the fact that the memo gave the Clinton campaign a role in communications hiring, Mook added, "The purpose of the DNC while a primary is going on is to hold Republican candidates accountable, and nobody was filling that post." He also insisted that the Sanders campaign had the ability to enter into a similar arrangement with the party.

Sanders and his supporters have long alleged that the DNC tipped the scales in the 2016 primary. A frequent piece of evidence cited for this was the decision to hold debates on weekends when viewership would be lower. Emails released by WikiLeaks on the eve of the 2016 Democratic National Convention showed that some DNC staffers favored Clinton and were vocal about it. U.S. intelligence believes those leaked emails originated with Russia's efforts to disrupt the 2016 campaign.

Brazile herself was eventually at the center of that controversy. Emails hacked from Clinton campaign chairman John Podesta and released by Wikileaks showed that Brazile, a former CNN commentator, passed along details about questions Clinton would receive at a primary debate and a candidate forum hosted by the network. Following those revelations, CNN ended its relationship with Brazile.

Current chairman Tom Perez was not at the DNC during 2016, but the contested primary and its lingering aftermath have loomed over the former labor secretary as he has tried to rebuild the party.

"Even a perception of impropriety — whether real or not — is detrimental to the DNC as an institution," he wrote in the letter to DNC members. "You have my commitment that 2020 will be a transparent process. That is why I want to make sure that the primary debate schedule is decided well ahead of the presidential primary process and why I stand by the essential work of the Unity Reform Commission."

That commission is charged with recommending changes to the Democratic primary process. On MSNBC, Weaver said its final conclusions — and whether or not they're adopted — will be a key indicator of whether the DNC stands behind its promise to be more welcoming to Sanders and his supporters.

Read the full memo, obtained by NPR from a Democratic source:

"This Memorandum is intended to memorialize our agreement regarding the creation and operation of Hillary Victory Fund (Victory Fund), a joint fundraising committee of Hillary for America (HFA) and the Democratic National Committee (DNC).

"HFA is prepared to raise and invest funds into the DNC via the Victory. In return for this financial support, HFA requires the appropriate influence over the financial, strategic, and operational use of these JFA-raised funds.

"Commencing on September 1, 2015 HFA agrees to raise funds for the Victory Fund sufficient to fund the DNC's data, technology, analytics, research, and communications operations. Specifically, HFA will agree to raise and to instruct the Victory Fund Treasurer, Beth Jones (who is employed by HFA) to transfer from the Victory Fund a minimum of one million and two hundred thousand dollars ($1,200,000.00) to the DNC from its share of the net proceeds under the allocation formula on the first day of every month (beginning October 1, 2015) for these activities (the "Base Amount"). In the event that the Victory Fund is not in possession of adequate net proceeds allocable to the DNC on the first of the month to make such transfer, it shall make the required transfer as soon as adequate funds are available.

"HFA's obligations under this agreement, and the release of the Base Amounts each month are conditioned on the following:

With respect to the hiring of a DNC Communications Director, the DNC agrees that no later than September 11, 2015 it will hire one of two candidates previously identified as acceptable to HFA.

With respect to the hiring of future DNC senior staff in the communications, technology, and research departments, in the case of vacancy, the DNC will maintain the authority to make the final decision as between candidates acceptable to HFA.

Agreement by the DNC that HFA personnel will be consulted and have joint authority over strategic decisions over the staffing, budget, expenditures, and general election related communications, data, technology, analytics, and research. The DNC will provide HFA advance opportunity to review on-line or mass email, communications that features a particular Democratic primary candidate. This does not include any communications related to primary debates – which will be exclusively controlled by the DNC. The DNC will alert HFA in advance of mailing any direct mail communications that features a particular Democratic primary candidate or his or her signature.

If asked by a State Party, the DNC will encourage the State Party to become a participant in the Victory Fund.

"Once HFA has raised the first $1,200,000 and it has been distributed to the DNC, HFA will be granted complete and seamless access to all research work product and tools (not including any research or tracking the DNC may engage in relating to other Democratic candidates).

"The parties also agree that they will enter into an agreed upon voter file licensing agreement. As consideration for that agreement, HFA will raise an additional $250,000 into the Victory Fund that will be distributed to the DNC no later than March 31, 2016.

"In addition, HFA will also raise funds for the Victory Fund that will distributed to the DNC in excess of the $1,200,000 monthly base amount (Excess Amount). The Excess Amount raised by HFA that is distributed to the DNC will be spent on the DNC's data, technology, analytics, research, and communications operations as directed by HFA (Special Projects). Although the DNC will remain responsible for the day to day execution of those Special Projects, HFA will determine (in consultation with the DNC) the Special Project's scope, strategy, staffing, budget, and manner of execution.

"Finally, HFA agrees that on a monthly basis the Victory Fund will provide the DNC a list of receipts and disbursements from the Victory Fund. The DNC agrees to provide monthly financial reports to HFA as it relates to the use of the funds distributed by the Victory Fund to the DNC.

"In the event that there is a disagreement in the operation of this agreement or the use of the Base Amount, the DNC department head and their HFA counterpart will meet and confer to resolve the matter. If that fails to resolve the disagreement, then you and I will resolve it. If there is still no resolution the DNC Chair and the HFA Chair will resolve.

"Nothing in this agreement shall be construed to violate the DNC's obligation of impartiality and neutrality through the Nominating process. All activities performed under this agreement will be focused exclusively on preparations for the General Election and not the Democratic Primary. Further we understand you may enter into similar agreements with other candidates.

"The attached Joint Fundraising Agreement will be entered into by HFA and the DNC (as well as by State Parties).

"This agreement will be reviewed on March 31, 2016 and either party may terminate any prospective obligation at that time.

Now, it's been a rough few days for Democrats, too. They are trying to rebuild and win elections, including two gubernatorial races next week. And yet the 2016 Democratic primary is a wound that just can't seem to heal. Donna Brazile, who served last year as interim chair of the Democratic National Committee, dropped a bombshell this week. She says the DNC was effectively under control of the Clinton campaign, and lots of Democrats are angry about what this might have meant to last year's primary. Here's a taste of that. This is CNN's Jake Tapper questioning Democratic Senator Elizabeth Warren.

(SOUNDBITE OF ARCHIVED RECORDING)

JAKE TAPPER: Very quickly, Senator, do you agree with the notion that it was rigged?

SCOTT DETROW, BYLINE: This all comes from an excerpt from a new book. Remember; Brazile took over the party last summer after Debbie Wasserman Schultz was forced out as DNC chair. Brazile says shortly after she took over, she found a formal agreement between the DNC and the Clinton campaign.

The long and short of it was that the Clinton campaign would raise a lot of money for both the campaign and the DNC and help pay off the commission's debt. But in exchange, the Clinton campaign would have a say in DNC staffing decisions, communications and party strategy. And what's key is that this document was signed in 2015 before Clinton became the party's nominee, in fact before any primary votes were ever cast.

KELLY: What's the DNC saying? Are they pushing back on this?

DETROW: A little but not quite. It's a word parsing exercise here. DNC chairman Tom Perez says the DNC had joint fundraising agreements with the Clinton campaign, with the Sanders campaign as well and that the language was exact in both and that these agreements were not made.

I have tracked down that fundraising agreement between the DNC and the Clinton campaign. It does not in fact include any of these agreements about staffing and policy and big decisions like that. But two senior Democratic officials have now told me that what Brazile is talking about is in fact a totally separate agreement with the Clinton campaign Aside from these joint fundraising agreements.

KELLY: All right, that sounds like something we haven't heard before about this whole situation.

DETROW: Yeah. This is new. And there was a lot of uncertainty about what exactly Brazile was talking about here. But this is a separate document between the DNC and the Clinton campaign signed on August 26, 2015. What's interesting there, among many other things, is that this was before Vice President Joe Biden decided whether or not he was going to run for the Democratic nomination.

KELLY: All right - so lots of details, lots of questions here. But do I hear you right that we now essentially have everybody from Elizabeth Warren to President Trump saying this is proof the whole thing was rigged? I mean, these are two names you never thought you'd heard agree about anything (laughter).

DETROW: Well, it's not quite that boiled down. It's not quite that simple. I mean, remember; Hillary Clinton did win the Democratic primary. She won it with a wide margin both in raw votes and with pledged delegates. And nobody has ever indicated the voting process was affected in any way. And we've known the general picture here for a long time.

Remember those WikiLeaks emails that came out right at the beginning of the the Democratic Convention. Of course we now know that the - that U.S. intelligence says that was part of a deliberate effort by Russia to meddle in the election. But there were lots of staff emails, lots of clear signs that the DNC did favor Clinton in spirit if not in any sort of scale pushing or anything like that.

KELLY: But what does this mean for the Democratic Party? I mean, is this party ever going to be able to move on from 2016?

DETROW: (Laughter) It often seems like that's not the case. The DNC wants to move on. They need Bernie Sanders' supporters to move forward and win elections like next week's elections. But feelings are still raw. And every time something like this happens, they all come back to the surface. And that mistrust is still there.